1. Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display device. More particularly, the present invention relates to an organic light emitting diode (OLED) display device having improved display characteristics.
2. Description of the Related Art
An organic light emitting diode display device includes a plurality of organic light emitting diodes that include hole injection electrodes, organic emission layers, and electron injection electrodes. Energy is produced when excitons generated by combination of holes and electrons in the organic emission layer transit from an excited state to a ground state to emit light, such that the organic light emitting diode display device forms visual images.
Therefore, the organic light emitting diode display device has a self-emission characteristic. Unlike a liquid crystal display device, since the organic light emitting diode display device does not require an additional light source, the thickness and weight of the organic light emitting diode display device can be reduced. Further, since the organic light emitting diode (OLED) display device shows high-quality characteristics such as low power consumption, high luminance, and high reaction speed, the organic light emitting diode display device has attracted considerable attention as a next-generation display device for a portable electronic apparatus.
In general, one or more of the hole injection electrodes and the electron injection electrodes, and various other metal wires that are disposed in the organic light emitting diode display device, can reflect light inputted from the outside. Accordingly, when the organic light emitting diode display device is used in a bright environment, representation and contrast of a black color are undesirably deteriorated due to external light reflection.
In order to solve the problem, a polarizing plate and a phase retardation plate are disposed on an organic light emitting element to suppress the external light reflection. A known method of suppressing the external light reflection by means of the polarizing plate and the phase retardation plate has a problem, however, in that a large amount of light generated from the organic emission layer is lost when being discharged to the outside through the polarizing plate and the phase retardation plate.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.